This section describes approaches that could be employed, but are not necessarily approaches that have been previously conceived or employed. Hence, unless explicitly specified otherwise, any approaches described in this section are not prior art to the claims in this application, and any approaches described in this section are not admitted to be prior art by inclusion in this section.
The Internet Engineering Task Force (IETF) is attempting to propose standards that can be applied to wireless devices for the stringent requirements of deterministic networks (e.g., minimal jitter, low latency, minimal packet loss). For example, Low power and Lossy Networks (LLNs) allow a large number (e.g., tens of thousands) of resource-constrained devices to be interconnected to form a wireless mesh network. The IETF has proposed a routing protocol (“6TiSCH”) that provides IPv6 routing using time slotted channel hopping (TSCH) based on IEEE 802.15.4e, enabling LLN devices to use low-power operation and channel hopping for higher reliability.
The 6TiSCH architecture specifies a Channel distribution/usage (CDU) matrix of “cells”, each cell representing a unique wireless channel at a unique timeslot. The 6TiSCH architecture also specifies installation of a track allocating a sequence of cells for each hop along a path from a source to a destination, for deterministic forwarding of a data packet. Loss of the data packet along the track, however, results in unused cells “downstream” of the network device that lost the data packet.
Deterministic transmission in wired networks can use time sensitive networking (TSN) and/or audio/video bridging (AVB). Neither TSN nor AVB use time slots; rather, TSN uses time-based shapers that allocate time slices and guard bands to cause a data packet to be sent or received at a given intermediate node (i.e., hop) along a path at a prescribed precise time that is reserved exclusively for the given hop; AVB can use credit-based shapers that ensure bounded latency transmit/receive queues in each hop without congestion, thereby ensuring a bounded latency.